I was just wondering if you could tell me the steps how to do that problem because I'm still confused how you got that answer.

That symbol I used (the paranthesis) the number of combinations. Over here it represents the number of ways selecting 7 objects from 45. You use the following formula,
Where the factorial, means, the product of all numbers before it.
For example,

Factorials, get large, quickly.
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Thus, if you wanted to know what would be for 8 out of 45 then it would be,
And now just use a super calculator (like the one on your computer).